Adjustable modular staircase

ABSTRACT

The present invention concerns a modular and adjustable staircase, prefabricated, destined to be installed in a rigid manner, and having at least one side which is equipped with a stiffener (1). Per stair and per side having a stiffener (1), a single element of the staircase, which is a crosspiece equipped with a heel (7a), of a shim (6), must be adjusted or is predetermined is order to obtain the desired stair height.

This application is a national stage application, according to ChapterII of the Patent Cooperation Treaty.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

The present invention concerns a modular and adjustable staircase,prefabricated, designed to be installed in a rigid manner, and having atleast one side which is equipped with a stiffener. Per stair and perside having a stiffener, a single element of the staircase, which is across piece with a heel, or a shim, must be adjusted or is predeterminedin order to obtain the stair height desired. The shim is an element thatis placed under the bottom side of the crosspiece to adjust the heightof the step. The crosspiece with heel is a one piece element whichlikewise determines the height of the step.

Definitions of the terms used in the description and the claims:

floor to floor spacing: the space which separates the levels of astorey, that is, the vertical distance between the upper floor and thelower floor of the place where the present invention is to be installed.

rear of a stair: the part opposite the nosing.

tread: the horizontal spacing between two stair nosings, measured alongthe line of stride.

width of a stair: horizontal spacing which is perpendicular to thetread, measured between the stair extremities.

height of a stair: vertical distance between the level of the lowerfloor and the first stair, or between two consecutive stairs, or betweenthe last stair and the level of the upper floor.

constant stair height: height obtained by dividing the floor to floorspacing by the number of stairs plus one.

The present invention, tending to bring improvements to patent #92 06170published under #2691 489, differs from the prior techniques by itspossibility for adjusting the heights of stairs and/or the tread and/orthe width of each stair, which makes the staircase multi-purpose andsuitable for installing in spaces with dissimilar volumes.

Thus the installation of the staircase can form only constant stairheights. Most of the known manufactured staircases require a staircasestarting base which can be cut off at the top; which, compared to thevertical spacing of the other stairs shows a disparity in height whichis detrimental to the climbing or descending cadence of the user. Thebase makes the structure uncomfortable and dangerous because of thisdisparity in height.

Patent DE-A-2619804 filed by the Carl Rehfeldt cement factory, describesseveral configurations for prefabricated staircases designed to be builtusing fiberglass-reinforced concrete. Contrary to the present invention,the various configurations described, as well as their manner ofproduction, allow neither an adjustment of the geometry of a type ofelement of the prefabricated staircase, nor a choice of position andorientation of certain of the elements of the staircase in relation toone other in order to result in a possible in situ adjustment of theheight and tread of the stairs, whereas the present invention allows allof that.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE

According to a specific embodiment, the present invention is a staircaseinstalled between two floor levels (FIG. 1). In the figure we see astiffening element (1) connected to the vertical piece (3B) serving asthe lower newel and to the upper newel (3E), as well as vertical pieces(4A, 4A1, 3B) traversing peripheral modules (12) and connected to thecrosspieces with a heel (7a) or shim (6) equipping a crosspiece (7),which support stairs (5, 16).

There are three types of vertical pieces (4A, 4A1, 3B) attached tostiffener (1), which might be rectangular in cross section with roundededges. The bottoms of vertical pieces (4A, 4A1) are perforated with twosuperimposed vertical slits (9a, 9b) (FIG. 2) of different heights. Theupper slit (9a) is of the high type with respect to slit (9b).

BRIEF DESCRIPTION OF THE DRAWINGS

Some of the objects of the invention have been set forth above. Otherobjects and advantages of the invention will appear as the descriptionproceeds when taken in conjunction with the following drawings, inwhich:

FIG. 1 is an elevational view of an adjustable modular staircaseaccording to one preferred embodiment of the present invention;

FIG. 2 is a cross-sectional view taken through vertically-spacedcrosspieces;

FIG. 3 shows the module and stair;

FIG. 4 shows the crosspiece and vertical piece; and

FIG. 5 is a cross-sectional view taken through the module and stair.

Vertical piece (3B) is perforated in its lower part by a slit (9a) ofthe high type.

Vertical piece (4A1) is different from vertical piece (4A) by itsslightly longer length. The center distances of the axes of slits (9a)and (9b) are identical on both vertical pieces of unequal height. At thelevel of each slit (9a, 9b) are provided, perpendicularly to their axes,superimposed perforations (14) placed in such a way as to allow thepassage of the fastening components, which may be trunnions (FIG. 1).

The specific form or crosspieces (7a) and crosspieces (7) equipped withshims (6) allows adjustment of the tread and the height of each stair.

The crosspieces fit into the upper slit (9a) (FIG. 2) of vertical pieces(4A, 4A1) or in the lower slit of vertical piece (3B).

The lower part of the said crosspieces (7a) includes a heel, which is aprojecting part, or a shim (6) which rests upon the lower part of slit(9a) of each vertical piece. Each slit (9b) rests upon part of eachcrosspiece (7, 7a).

Stairs (5, 16) (FIGS. 1, 3) are perforated at each of their extremitieswith holes (9, 15), which may be rectangular with rounded angles,allowing for the passage of vertical pieces (3B, 4A, 4A1) which transfixthem while leaving free access to slits (9a, 9b).

The said slits may be rectangular with rounded angles.

(Slit 9b) is provided for in order to receive the part of crosspiece(7a) or of crosspiece (7) equipped with its shim (6) which has thegreatest height. The part of crosspiece (7), (7a) which has the smallestheight is designed to be inserted into slit (9b) (FIGS. 1, 2).

In each stair (5) or (16) have been contrived holes (9) or (15) of whichthe treadwise dimension is greater than the treadwise dimension of thevertical pieces (4A, 4A1) going through the holes (9), or of (3B) goingthrough the holes (15). This arrangement combined with the possibilityfor sliding crosspieces (7, 7a) in the slits (9a, 9b) allows for theadjustment of vertical pieces (4A, 4A1) or (3B) with respect to stairs(5) or (16), to crosspieces (7, 7a) and to the shims (6). This allowsobtaining inter alia the adjustment of the tread of the stairs. It ispossible to modify the horizontal space between the vertical pieces (4A)and (4A1) of each stair.

Peripheral modules (12, 12A), which include a hole (9c) through whichpass vertical pieces (4A, 4A1, 3B) slide and come to rest on each one ofthe components traversing the stairs (5, 16). The geometry of theseperipheral modules allows for concealing the holes (9, 15) of thestairs.

At least one stair of the present invention includes on its uppersurface, a system which makes it partially or totally nonskid.

The rear of the stair has a relief which serves as a stop to prevent thefoot from going further.

Reference is made here to the aforementioned drawings to describe theadvantageous, but non-limiting, embodiment of the staircase according tothe invention.

Other embodiments of this staircase, of which the line of stride mayhave curves and/or broken lines, are possible according to the presentinvention.

I claim:
 1. A modular and adjustable staircase for being installedbetween floor levels of different heights, and including stairs allowingpassage from one level to the other, said staircase comprising:(a) arail stiffener located on at least one side of the staircase; (b) atleast one vertical piece having top and bottom ends, the top end beingsecured to the stiffener and the bottom end extending downwardly towardsthe stairs and having at least one crosspiece-receiving opening therein;and (c) a stair-supporting crosspiece with an enlarged heel receivedwithin the opening of said vertical piece, said heel determining therelative height of a stair supported by said crosspiece.
 2. A staircaseaccording to claim 1, wherein the vertical distance between each of thestairs is constant by the aid of the crosspiece and said heel.
 3. Astaircase according to claim 1, wherein the vertical piece includesupper and lower crosspiece-receiving openings formed in said bottom endfor receiving respective first and second crosspieces.
 4. A staircaseaccording to claim 3, wherein the upper opening in the vertical piecehas a greater height than the lower opening.
 5. A staircase according toclaim 1, wherein each stair has an enlarged opening formed adjacent aside edge thereof for allowing passage of the vertical piece which joinsthe stiffener to the crosspiece.
 6. A staircase according to claim 5,and including a peripheral module residing adjacent each of said stairsand having an opening therein and receiving the vertical piecetherethrough, said module being of a size and shape sufficient toconceal the enlarged opening of each of said stairs, and said modulecooperating with fasteners to immobilize the stairs on the crosspiece.7. A staircase according to claim 1, wherein a tread surface of thestair is adjustable by sliding the vertical piece and crosspieceforwardly or rearwardly relative to the stair.
 8. A staircase accordingto claim 1, wherein at least one of the stairs has a non-skid uppersurface.
 9. A staircase according to claim 1, and comprising a relieflocated at a rear edge of the stair for providing a stop.
 10. A modularand adjustable staircase for being installed between floor levels ofdifferent heights, and including stairs allowing passage from one levelto the other, said staircase comprising:(a) a rail stiffener located onat least one side of the staircase; (b) at least one vertical piecehaving top and bottom ends, the top end being secured to the stiffenerand the bottom end extending downwardly towards the stairs and having atleast one crosspiece-receiving opening therein; (c) a stair-supportingcrosspiece received within the opening of said vertical piece; and (d) ashim positioned within the opening of said vertical piece between thecrosspiece and a bottom surface of the opening for adjusting therelative height of a stair supported by said crosspiece.
 11. A staircaseaccording to claim 10, wherein the vertical distance between each of thestairs is constant by the aid of the crosspiece and shim.
 12. Astaircase according to claim 10, wherein the vertical piece includesupper and lower crosspiece-receiving openings formed in said bottom endfor receiving respective first and second crosspieces.
 13. A staircaseaccording to claim 12, wherein the upper opening in the vertical piecehas a greater height than the lower opening.
 14. A staircase accordingto claim 10, wherein each stair includes an enlarged opening formedadjacent a side edge thereof for allowing passage of the vertical piecewhich joins the stiffener to the crosspiece.
 15. A staircase accordingto claim 14, and including a peripheral module residing adjacent each ofsaid stairs and having an opening therein and receiving the verticalpiece therethrough, said module being of a size and shape sufficient toconceal the enlarged opening of each of the stairs, and said modulecooperating with fasteners to immobilize the stairs on the crosspiece.16. A staircase according to claim 10, wherein a tread surface of thestairs is adjustable by sliding the vertical piece and crosspieceforwardly or rearwardly relative to the stairs.
 17. A staircaseaccording to claim 10, wherein at least one of the stairs has a non-skidupper surface.
 18. A staircase according to claim 10, and comprising arelief located at a rear edge of each of the stairs for providing astop.